Success!!! It appears that if you plant your crops after the Nile has flooded they actually grow! :)
While we didn't plant any additional seed this week (we had such a bumper crop there wasn't any room) we decided to go ahead and flood the Nile one final week. I can report that at the end of Week 5 our grass was going wild and was so tall it was all falling over.
My (very) brief attempt at creative photography... I think it would have been a cool picture if I could have figured out how to get the camera to focus on the girl's faces instead of the grass. Oh well! :)
This has been a great experiment to watch and learn about the Nile from for several weeks. We're looking forward to many future Story of the World projects!